Envision Math 3rd Grade Topic 10 and 11 Vocab flashcards

Terms	Definitions
Congruent	A figure that has the same size and shape as another figure.
Translation	Moving a figure by sliding it up, down, left, or right; also called a slide.
rotation	Moving a figure by turning it around a point; also called a turn.
reflection	Moving a figure by picking it up and flipping it over; also called a flip.
line of symmetry	A line on which a figure can be folded so the two parts match exactly.
symmetric	A figure is symmetric if it has at least one line of symmetry.
parallelogram	A quadrilateral with two pairs of parallel sides.
trapezoid	A quadrilateral with exactly one pair of parallel sides.
rhombus	A special parallelogram in which all sides are the same length.
rectangle	A quadrilateral with four right angles.
square	A quadrilateral with four right angles and all sides the same length.
isosceles triangle	A triangle with at least two sides having the same length.
equilateral triangle	A triangle having three sides the same length.
right triangle	A triangle in which one angle is a right angle.
scalene triangle	A triangle in which no sides have the same length.
obtuse triangle	A triangle in which one angle is an obtuse triangle.
acute triangle	A triangle in which all three angles are acute angles.
triangle	A polygon with 3 sides.
vertex of a polygon	The point where two sides of a polygon meet.
pentagon	A polygon with 5 sides.
quadrilateral	A polygon with 4 sides.
octagon	A polygon with 8 sides.
hexagon	A polygon with 6 sides.
perpendicular lines	Two lines, line segments, or rays that make a right angle.
right angle	An angle that makes a square corner.
obtuse angle	An angle that is open more than a right angle.
acute angle	An angle that is open less than a right angle.
side	A line segment that forms part of a polygon.
polygon	A closed figure made up of line segments.
line segment	A part of a line with two endpoints.
line	A set of points that forms an endless straight path in opposite directions.
parallel lines	Lines that never cross.
intersecting lines	Lines that cross at one point.
angle	Two rays with the same endpoint; that endpoint is the vertex of the angle.
ray	A part of a line with only one endpoint.
face	A flat surface of a solid figure that does not roll.
sphere	A solid figure in the shape of a ball.
vertex	A point where three or more edges of a solid figure meet.
edge	A line segment where two faces of a solid figure meet.
point	An exact position, often marked by a dot.
vertices	The plural form of vertex.
rectangular prism	A solid figure with faces that are rectangles.
solid figure	A geometric figure that has length, width and height.
pyramid	A solid figure whose base is a polygon and whose faces are triangles with a common point.
cube	A solid figure with faces that are squares.
cone	A solid figure with a circle as its base and a curved surface that ends in a point called the vertex.
cylinder	A solid figure with two congruent circles as bases.